1. Field of the Invention
This invention generally relates to a guide assembly for a movable member, and to such a guide assembly including a channel-shaped guide track and one or more guide rollers. More particularly, the guide rollers are supported forvariable adjustment and are yieldingly biased toward respective guide track surfaces to accommodate misalignment in the guide track.
2. The Prior Art
In environments such as offshore drill rigs where certain members may be vertically moved and supported by rigid guide rail structures, damage is often encountered in guide roller assemblies or in the guide tracks as a result of misalignment in the track or as a result of shock loads. Such damage from misalignment is caused by the high loads placed on the components moving relative to each other and is particularly acute in offshore drill rigs, because the rig typically heaves and pitches from wave action.
In the past, the guide assemblies for vertically moving members, such as traveling blocks or motion compensators in a drill rig, have included either two fixed rollers or a single, larger roller positioned between guide surfaces of a channel shaped track. Invariably in this environment, the guide tracks become misaligned due to the constant forces from the elements, such misalignment causing failure in the rollers or roller bearings or damage to the rails. Repairing such damage involves not only the economics or replacement parts, but also requires down time for the vertically moving member during repairs.
As a result, the prior guide roller assemblies have included certain disadvantages, deficiencies, and drawbacks which have required their replacement due to premature failures.